make compat with sf5.0 form and parameter type declarations in conjun…

[phiamo]

make compat with sf5.0 form and parameter type declarations in conjunction with the CollectionType

When using the Collection Type we get numbers (indice of the form collection) as keys, since they are int's
the symfony5.0 type declaration throws an exception since it requires a string.

Casting to string before all calls fixes this

I am targeting this branch, because it would make next version compatible with symfony5.0 as well.

Changelog

### Changed
- Cast form name to string for symfony5.0 compatibility

[VincentLanglet]

I kinda wonder if there is a way to cast the name somewhere else (before this class) in order to do the cast only once. But I have no idea;

[phiamo]

I was wondering the same, but after thinking a bit about it, its the duty of this class to iterate over collections and detect size etc.
Just wondering how to symfony resize listener handles that case ...

[greg0ire]

I don't have a better solution to propose, so let's approve. This needs to be squash-merged (or you can squash it yourself, OP)

How to do that?

1. git rebase -i origin/3.x, assuming origin is a git remote that points to this repository, and not your fork. If you're not sure what your remotes are, run git remote -vvv, there should be your fork and the holy/reference/base/origin/whatever-you-call-it repository.
2. A window will show up with many lines, replace pick with fixup on every line but the first one
3. Close your editor, git should do its magic, and you should end up with one commit
4. Use git push --force to overwrite what you already push. Don't forget the --force option otherwise git will try to merge both things together.

[greg0ire]

Thanks @phiamo !

[SonataCI]

Ok @franmomu,

I requested a new release for form-extensions via Slack in #releases channel 👍

If you want to get notified about new releases, make sure to follow SonataNews on Twitter!

[franmomu]

Just wondering how to symfony resize listener handles that case ...

They don't declare strict_types, I guess that's why it works.